Multiple electrical connector

ABSTRACT

A multiple electrical connector for a printed-circuit board embodying a receptacle having an open-topped trough for receiving a printed-circuit board and contact elements spaced from one another along said receptacle trough, featured by contact elements formed in the flat as from a sheet of conductive material and each comprising a base and a pair of spring legs of different lengths extending up from the base, the contact element being positioned in the receptacle in a plane normal to the plane of the printed-circuit board. The spring legs provide a redundancy in that the legs function independently to provide an electrical connection to the contact areas of the board and have independent deflection and resonant frequencies.

United States Patent [72] Inventor Robert B. Pittman River Edge, NJ

[211 App]. No. 25,134

[22] Filed Apr. 2, 1970 [45] Patented Dec. 28, 1971 [73] AssigneeIndustrial Electronic Hardware Corp.

New York, N.Y.

[54] MULTIPLE ELECTRICAL CONNECTOR Primary Examiner-Marvin A. ChampionAssistant ExaminerLawrence J. Staab Attorney-James and FranklinABSTRACT: A multiple electrical connector for a printed'circuit boardembodying a receptacle having an open-topped trough for receiving aprinted-circuit board and contact elements spaced from one another alongsaid receptacle trough, featured by contact elements formed in the flatas from a sheet of conductive material and each comprising a base and apair of spring legs of different lengths extending up from the base, thecontact element being positioned in the receptacle in a plane normal tothe plane of the printed-circuit board. The spring legs provide aredundancy in that the legs function independently to provide anelectrical connection to the contact areas of the board and haveindependent deflection and resonant frequencies.

MULTIPLE ELECTRICAL CONNECTOR This invention relates to a microminiaturemultiple electrical connector for use with a printed circuit board.

In multiple electrical connectors for use with a printed-circuit board,a large group of miniature contact elements are mounted in closelyspaced relation in a receptacle having an open-topped trough forreceiving a printed-circuit board containing a correspondingly largegroup of closely spaced conductive contact areas adapted for matingcontact with said contact elements. The multiple connector andparticularly, the multiple contact elements thereon must be so designedas to assure the effective electrical engagement of the contacts and theclosing of all of the involved circuits. In multiple electricalconnectors of prior makes, the contact elements supplied were generallyeither tuning fork or ribbon-type" contacts, the ribbon contacts being.generally either the single leaf, multiple-leaf or bellows" type. All ofthese types of contact elements were designed to assure engagementbetween the contact elements and the conductive contact areas of theprinted circuit board.

Other problems of concern in the manufacture and use of these multipleminiature connectors are providing a structure for the receptacle andthe contact elements such that a printed-circuit board could be insertedand removed without causing damage or excessive wear to either thecontact elements or to the conducting areas on the board. Within limits,the greater the pressure which a contact element exerts on theconducting areas on the board, the better is the electrical connectionwhich results and, this is a usually very important factor, particularlywhen very low voltages are involved as in computer input and outputsignals. Too great a contact pressure, however, has the effect of makingit more difficult to insert or remove a board from the connector,resulting also in increasing the wear on the contacts and particularlythe very thin conducting areas on the board. The various types and formsof contact elements supplied in prior design are devised to solve theseproblems, the solution of which usually involves a compromise ofsatisfying the different factors or requirements involved.

In addition to these problems are others which so far as I am aware arenot effectively dealt with in the design of these prior type of multipleconnectors; and it is to these problems, in addition to those abovereferred to, that the structure of the present multiple-connectorinvention is addressed. Such additional problems involve the doubleassurance of effecting the desired contact engagements particularly inequipment which is subject to vibrations, intermittent or constant, orto sudden shock as when the equipment is used on vehicles in transit andparticularly on aircraft, such vibrations or shock causing contactweakening and interruptions to take place in the connector withresulting circuit interruptions.

The prime object of the present invention is directed to the provisionof a structure and a design of a miniature electrical connector having acontact element embodied in the form of a tuning fork type, in which inaddition to solving the usual problems that are met with as abovereferred to, there is introduced a redundancy in the operation of thecontact element which is not available, so far as known to me, in any ofthe existing tuning fork contact designs and not possible to achievewith a bellows-type contact element in the microminiature class ofconnectors. in the structure of the present invention, a redundancy isintroduced by providing a plurality of members or parts in the contactelement functioning independently to effect electrical contact with thecontact area on the board which members have as well deflectionproperties independently of each other, and also have different resonantfrequencies to meet different vibration frequencies to which theconnector may be subjected in use.

A further important object of the invention is the devising of a contactelement for miniature connectors satisfying the various needs abovereferred to, which can be made and supplied at a reasonable cost andalso one which can be mounted in or assembled to the connectorreceptacle easily and securely.

To the accomplishment of the foregoing objects and such other objects asmay hereinafter appear, my invention relates to the multiple electricalconnector as sought to be defined in the appended claims and describedin the following specification, taken together with the accompanyingdrawings in which:

FIG. 1 is a perspective view, in exploded form, of the parts comprisingthe electrical connector of the invention, consisting of the receptacleand the contact elements associated therewith;

FIG. 2 is a vertical cross-sectional view, shown to an enlarged scale,of the assembled parts of the electrical connector;

FIG. is a bottom plan view of the receptacle depicted'in FIG. 1 andshown on a reduced scale;

FIG. 4 is a vertical elevational view shown to an enlarged scale of oneof the contact elements of the connector;

FIG. 5 is a side elevational view of the contact element shown in FIG.4;

FIG. 6 is a view of a part of the contact element taken in cross sectionin the plane of the line 6-6 of H64; and

FIG. 7 is a view of another part of the contact element taken in crosssection in the plane of the line 7-7 of FIG. 4.

Referring now more in detail to the drawings and having reference firstto FIGS. 1 and 2 thereof, the microminiature multiple electricalconnector of the present invention comprises a receptacle generallydesignated as R structured to receive a substantial number of connectorelements each generally designated as C, which latter are especiallydesigned in accordance with the above-stated principles of theinvention.

The receptacle R, made of a single molded piece of insulation material,is formed with a central longitudinal trough 10 for receiving a printedcircuit board B, the said trough being defined by two oppositely facingwalls 12 and 14, at least one and preferably both of which walls areformed with a plurality of pockets l6, l6, spaced longitudinally alongthe trough corresponding in number to the number of contact elements Creceived by the receptacle, each contact element being located andpartially housed by a pocket 16. The receptacle R may also be formedwith perforated terminal lug portions 18 (only one being shown in thedrawings) for the reception of attaching elements.

The contact elements C are each structured in the form of a tuning forkor bifurcated member, the same being formed from a sheet of conductivematerial made to comprise a base 20 and a pair of spring legs 22 and 24extending up from the base, the said spring legs, lying in the sameplane, being of different lengths as clearly depicted in the drawings.The two spring legs 22, 24 have top laterally extending portions 26 and28, respectively, adapted to engage the contact areas 30, 30 on theboard B. Each contact element is also formed with one or more tails 32(one being depicted in the drawings) defining an electrical terminal. Asindicated, the contact elements are formed from sheet stock, therebybeing produced in the flat as shown, the said sheet-formed contactelements being thereby structured to be each positioned in a pocket 16of the receptacle in a plane normal to the plane of the printed circuitboard as best indicated in FIGS. 1 and 2 of the drawings.

As noted, the spring legs 22 and 24 are of different lengths. With thisconstruction of the contact elements and their location and arrangementin the receptacle, each of the spring legs 22, 24 functionsindependently to provide an electrical connection with the contact area30 on the board, and thereby a redundancy is introduced by the secondleg of the contact element in the operation of the connector. Inaddition, the base 20 of each contact element is formed with a slot 34between the spring legs configured to determine different contactpressure or load characteristics that may be applied to said legs. Eachcontact element is thus specially constructed of members or parts (thetwo spring legs) in the contact element functioning independently ofeach other to effect electrical contact with the contact area on theboard, the said members having as well deflection propertiesindependently of each other and also having different resonantfrequencies to meet the different vibration frequencies to which theconnector may be subjected in use.

The structure described also allows several choices loadcharacteristics, namely, a load equal for both spring legs, a load onthe long leg less than that on the short leg, and a load on the shortleg less than the load on the long leg; these choices are'controlled bydetermining the configuration at the lower end of the slot 34 betweenthe spring legs.

As above described, the contact elements are formed from a sheet inchconductive material; the material is preferably phosphor bronze, andpreferably gold or silver plated. Such sheet material may comprise stockhaving a thickness of 0.025 inch as indicated in FIG. 6 of the drawings.The width of each spring leg 22, 24 is also of the order of 0.025 inchas indicated in FIG. 4. The width of the top of the leg 22 including theprotuberance 26 may be 0.122 inch as indicated in FIG. 6, and the widthof the top of the spring leg 24 including its lateral protuberance maybe 0.067 inch as indicated in FIG. 7 of the drawings. The thickness ofdifferent boards B used may be of the order of 0.060 to 0.070 inch.These dimensions in addition to the 0.050 spacing between the centers ofthe pockets l6 serve to indicate the micro miniature character of theconnector.

The base of each contact element is formed with lateral protuberances 20and 20 for engagement with walls 16 and 16 of the pocket 16 of thereceptacle for securely mounting the contact elements at the base of thereceptacle; and extra nibs or bumps 36 are formed at least in one of theprotuberances of each contact element to retain the contact elements inthe receptacle through an interference fit. This mounting permitscomplete freedom of contact adjustment and movement of the two tines orspring legs 22 and 24 of the tuning fork like contact element. Thecontact-engaging tips of the top protuberances 26, 38 of the spring legsare preferably suitably coined at 38, 28 to render the same contactsmooth. While the contact elements in the described connector aredetailed as a double-sided, single-readout device, the same may befurnished for single-sided use and for double-readout use, the latterfunction being obtained by adding an additional tail to the contactelement. The terminal tails as shown are squared for wire wrap use, butmay be shaped for solder use.

As shown,'the right and left side contact elements are reversely shapedas mirror images. The contact elements on each side are preferablyarranged in staggered form as clearly appears in FIG. 2 and as is bestindicated by the staggered arrangement of the tails 32, 32 in FIG. 3.This facilitates the wire wrapping of the terminals. With the staggeredarrangement, left side contact elements may also be used on the rightside and vice versa. I

The operation of the connector, the uses and functions which aresatisfied by the contact elements, and the advantages thereof over priorart devices, will in the main be fully apparent from the above-detaileddescription. In operation and use, in addition to accomplishing thecustomary functions of assuring engagement between the contact elementsand the conductive contact areas of a printed-circuit board, ofpermitting reliable insertion and ease of removal of the contactelements and of inhibiting or minimizing damage or excessive wear toeither the contact elements and the conducting areas of the board, thestructure of the connector of the present invention attains thefollowing purposes, functions and advantages;

a. a tuning fork type of connector element is provided having tines orspring legs of different lengths, each leg functioning independently ofthe other to provide a redundancy in that each leg afi'ords anindependent electrical connection with the contact area of the board;

b. the spring legs may be configured to determine different (or equal)contact pressures or load characteristics;

c. the spring legs Ere designed to have different resonant frequenciesto meet ifferent vibration frequencies that may be met with in service;

d. the contact element may be designed to be base-supported in theconnector receptacle to permit freedom of contact and adjustmentengagement with the printed circuit board; and

e. the contact element may be formed simply form sheet stock, yielding adevice, readily adaptable for use in a microminiature edge boardconnector at a low and reasonable manufacturing cost.

It will be apparent that changes may be made in the construction of theconnector described without departing from the spirit of the inventiondefined in the following claims.

lclaim:

l. A multiple electrical connector for a printed-circuit boardcomprising a receptacle having an open-topped trough for receiving aprinted-circuit board having conductive contact areas and contactelements spaced from one another along said receptacle trough, saidcontact elements each being formed from a sheet of conductive materialand comprising a base and inner and outer spring legs extending up fromthe base, said sheet-formed contact element being positioned in saidreceptible in a plane normal to the plane of the printed circuit board,said base extending laterally outwardly beyond said outer spring leg andbeing relatively snugly received in said receptacle, a substantiallateral clearance being defined between said receptacle and said outerleg, one of the spring leg being longer than the other, and the twospring legs having laterally extending portions adapted to engage thecontact areas on the board, each of said spring legs functioningindependently to provide an electrical connection with the contact areaon the board, and the said spring legs having deflection properties oneindependently of the other.

' 2. The multiple electrical connector of claim 1, in which the twospring legs of the contact element have different resonant frequencies.

3. The multiple electrical connector of claim I, in which the base ofthe contact element is formed with a slot between the spring legsconfigured to determine different contact pressure or loadcharacteristics that may be applied to said legs.

4. The multiple electrical connector of claim 1, in which the base ofthe contact element is formed with lateral protuberances for engagingwalls at the base of the receptacle for mounting and retaining thecontact element in the housing.

5. In a multiple electrical connector for a printed-circuit boardcomprising a receptacle having an open-topped trough for receiving aprinted-circuit board having conductive contact areas, a contact elementadapted to be received by said receptacle for connection to theconductive areas of said board, said contact element being formed from asheet of conductive material and comprising a base and inner and outerspring legs extending up from the base, said sheet-formed contactelement being positionable in said receptacle in a plane normal to theplane of the printed circuit board received therein, said base extendinglaterally outwardly beyond said outer spring leg and being relativelysnugly received in said receptacle, a substantial lateral clearancebeing defined between said receptacle and said outer leg, one of thespring legs being longer than the other and the two spring legs havinglaterally extending portions adapted to engage the contact areas on theboard, each of said spring legs functioning independently to provide anelectrical connection with the contact area on the board, and the saidspring legs having deflection properties one independently of the other.

6. The contact element of claim 5, in which the two spring legs havedifferent resonant frequencies.

7. The contact element of claim 5, in which the base of the contactelement is formed with a slot between the spring legs configured todetermine different contact pressure or load characteristics that may beapplied to said legs.

8. The contact element of claim 5, in which the base of the contactelement is formed with lateral protuberances for engaging walls at thebase of the receptacle for mounting and retaining the contact element inthe housing.

9. The multiple electrical connector of claim 1, in which said baseengages said receptacle with an interference fit.

13. The multiple electrical connector of claim 5, in which said baseextends laterally inwardly beyond said inner spring leg.

14. The multiple electrical connector of claim 5, in which when saidbase is received in said receptacle said inner leg is located outwardlyof said trough but the laterally extending portion of said inner legextends into said trough.

2. The multiple electrical connector of claim 1, in which the two springlegs of the contact element have different resonant frequencies.
 3. Themultiple electrical connector of claim 1, in which the base of thecontact element is fOrmed with a slot between the spring legs configuredto determine different contact pressure or load characteristics that maybe applied to said legs.
 4. The multiple electrical connector of claim1, in which the base of the contact element is formed with lateralprotuberances for engaging walls at the base of the receptacle formounting and retaining the contact element in the housing.
 5. In amultiple electrical connector for a printed-circuit board comprising areceptacle having an open-topped trough for receiving a printed-circuitboard having conductive contact areas, a contact element adapted to bereceived by said receptacle for connection to the conductive areas ofsaid board, said contact element being formed from a sheet of conductivematerial and comprising a base and inner and outer spring legs extendingup from the base, said sheet-formed contact element being positionablein said receptacle in a plane normal to the plane of the printed circuitboard received therein, said base extending laterally outwardly beyondsaid outer spring leg and being relatively snugly received in saidreceptacle, a substantial lateral clearance being defined between saidreceptacle and said outer leg, one of the spring legs being longer thanthe other and the two spring legs having laterally extending portionsadapted to engage the contact areas on the board, each of said springlegs functioning independently to provide an electrical connection withthe contact area on the board, and the said spring legs havingdeflection properties one independently of the other.
 6. The contactelement of claim 5, in which the two spring legs have different resonantfrequencies.
 7. The contact element of claim 5, in which the base of thecontact element is formed with a slot between the spring legs configuredto determine different contact pressure or load characteristics that maybe applied to said legs.
 8. The contact element of claim 5, in which thebase of the contact element is formed with lateral protuberances forengaging walls at the base of the receptacle for mounting and retainingthe contact element in the housing.
 9. The multiple electrical connectorof claim 1, in which said base engages said receptacle with aninterference fit.
 10. The multiple electrical connector of claim 1, inwhich said base extends laterally inwardly beyond said inner spring leg.11. The multiple electrical connector of claim 1, in which when saidbase is received in said receptacle said inner leg is located outwardlyof said trough but the laterally extending portion of said inner legextends into said trough.
 12. The multiple electrical connector of claim5, in which said base engages said receptacle with an interference fit.13. The multiple electrical connector of claim 5, in which said baseextends laterally inwardly beyond said inner spring leg.
 14. Themultiple electrical connector of claim 5, in which when said base isreceived in said receptacle said inner leg is located outwardly of saidtrough but the laterally extending portion of said inner leg extendsinto said trough.